Art is a work produced according to aesthetic principles. Mankind has a high regard for such works and, accordingly, is attracted to such works. It is known that dynamic objects may hold an observer's attention. For example, an observer may find himself staring at a rhythmically moving object, such as a grandfather clock pendulum, a tree branch swaying in the breeze, or a mobile. Watching such objects is both amusing and relaxing to the observer, as may be inferred from the use of mobiles to entertain infants lying in cribs. It is also known that different colors in a dynamic object, such as a pinwheel, holds an observer's attention.